The present invention relates to a wireless local area network comprising at least one server device, one or several peripheral devices, and means for transferring information between the server device and the peripheral devices. The invention relates also to a method for implementing a wireless local area network with at least one server device and one or several peripheral devices, in which local area network information is transferred between the server device and the peripheral devices. The invention relates further to a mobile station comprising means for setting up a connection to a wireless local area network, for transferring information between the mobile station and a device connected to the local area network.
Local area networks usually consist of one or several server computers as well as work stations and other peripheral devices communicating with the same, such as printers and telecopier devices. Data transmission in the local area network is usually implemented by using wires, such as Ethernet cabling. Also wireless local area networks are known, in which data transmission is implemented by means of radio modems. According to their structures, local area networks can be e.g. star networks, ring networks, segmented networks, or combinations of these. In a star network, the server is typically placed in the centre, and a data transmission connection is set up from the server to each peripheral device separately. Thus, communication takes place along cabling between the server and the peripheral device. In a ring network, the server and the peripheral devices are placed in succession to form a ring, wherein data is carried usually in one direction along this network. In this case, information sent by the server is transmitted to the next peripheral device in the ring which transmits it further, until the receiver of the information receives the information. In a segmented network, the server and the peripheral devices are also placed in succession, but there is a so-called terminal adapter after the last peripheral device in a segment. Data transmission is thus bidirectional. Also at the other end of the segment, there is a corresponding terminal adapter. In a ring network and in a segmented network, the respective order of the peripheral devices and the server device is usually not significant.
In local area networks, each peripheral device coupled to the local area network is provided with its own address which identifies the peripheral device and by means of which information is directed to this peripheral device. On the other hand, information coming from the peripheral device is identified in the server on the basis of the address of the peripheral device. In the peripheral device and the server, there is a network adapter determined according to the physical structure of the local area network used in the case, provided with means for receiving messages coming from the local area network and for transmitting messages to the local area network.
Data transmission in local area networks takes place typically as data transmission based on messages. A message consists of address data and the actual information to be transmitted. The message may also contain initial and terminal data on the message, for separating different messages from each other. The address data is used for directing messages to the correct device and, on the other hand, for identifying the device which sent the message.
Wireless local area networks differ from wired ones primarily in that data transmission is conducted by using a wireless data transmission method, such as radio waves or infrared light. In their principle of operation, wireless local area networks are typically star networks, i.e. data is transmitted between the server device and a peripheral device. Thus, information to be transmitted between peripheral devices is conducted from the sending peripheral device to the server which transmits the information further to the receiving peripheral device.
For operation of the local area network, the server must know which peripheral devices are coupled to the local area network at each time and what is the operating state of these peripheral devices. This can be implemented by using for example the above-mentioned, message-based data transmission, wherein the peripheral device sends a message to the server device when turned on and up on a possible change of state. The server device receives the message and examines the information content of the message.
The use of a local area wired network is limited e.g. by the location of cabling, and the number and location of connection points placed in the cabling. Expanding such a local area network will require cabling which in many cases is difficult and expensive, particularly afterwards. Some of these limitations of a local area wired network can be eliminated or their effect can be reduced by setting up the local area network by wireless techniques. However, presently known wireless local area networks are relatively expensive, which limits their use particularly in smaller local area networks.
The use of a local area network is usually limited to the premises of an office. A recent trend is, however, that part of the work that was previously done in the office is now done as remote work at home. In such cases, the transmission of data etc. between the home and the office can be facilitated if there is a compact data processor available with a sufficient storage capacity. An example of such a portable device is Nokia 9000 Communicator which can be used both as a mobile station and a data processor. The small size of the device, however, will usually to some extent limit e.g. the size of the user interface, such as the keypad and the display. Moreover, the storage capacity of the data processor does not necessarily provide the same data processing properties as larger data processors.
Also a portable data processor can be linked to a local area network by means of a network connection card provided with means for setting up a data transmission connection between the local area network and the portable device. The network connection card is coupled to the wired local area network by means of a cable suitable for this. The linkage to and the use of the local area network requires that the server device is in operation so that it is possible to use the other peripheral devices functionally coupled to the local area network, such as printers and a mass storage, from the portable peripheral device. The mass memory comprises for example one or several hard disk drives, on which it is possible to store e.g. application software, text files, image files, and other data files.
Different peripheral devices can be linked to portable data processors directly, without using a local area network. The linkage can also be based on wireless techniques, usually infrared (IR) techniques. When such a peripheral device is connected to a portable data processor or the like, the data on the peripheral device in question must be configured by the data processor before the peripheral device can be used. Furthermore, the number of peripheral devices that can be connected to the portable data processor is usually limited to one peripheral device at the time, which will reduce the usability of such a system. However, for usability, it is often better that several different types of peripheral devices are functionally connected to the data processor at the same time, for example a mass memory, a printer, and a modem.
One purpose of the present invention is to provide a local area network comprising one or several servers and one or several peripheral devices. It is possible to connect several peripheral devices to the local area network, and the detection of their connection can be made automatic, wherein the configuration is carried out by a data processor controlling the local area network. The local area network according to the present invention is primarily characterized in what is presented in the characterizing part of the appended claim 1. The method of the present invention is primarily characterized in what is presented in the characterizing part of the appended claim 5. Further, the mobile station of the present invention is primarily characterized in what is presented in the characterizing part of the appended claim 9. The invention is based on the idea that the local area network is formed by means of predetermined link agents. These link agents take care of not only configuration of the network but also routing of messages to the correct devices; for example, incoming telecopy messages are sent directly to the telecopier device, if necessary.
The invention gives significant advantages to local area networks, methods and mobile stations of prior art. Configuration of the local area network can be arranged to be conducted automatically for example in a situation in which a user enters the office carrying along a portable data processor or the like, which can be used as a server or a peripheral device. Thus, in accordance with an advantageous embodiment of the invention, the peripheral devices in the office and advantageously the server device carried by the user communicate with each other for setting up the configuration data of the local area network. In accordance with a second advantageous embodiment of the invention, the server device is arranged to be stationary, wherein the user carries along a peripheral device by means of which the user can control the server device to set up a personal local area network for the user.
By means of the arrangement of the invention, the user can set up a local area network for his/her use when he/she is in the office, at home or in another location where there are peripheral devices of the invention available. Thus, the user can make use of devices in said location without a need to connect his/her own data processor e.g. in a cable connection with these peripheral devices. On the other hand, setting up a personal local area network for the user will not essentially disturb other users, each of which being able to have a personal local area network set up.
The local area network of the invention can be easily implemented without wiring, wherein also the positioning of peripheral devices is more flexible. A peripheral device belonging to one local area network can simultaneously also belong to several local area networks, wherein the usability of each peripheral device is better than by using presently known local area network solutions. If necessary, the local area network of the invention can be linked also as a part of the local area network in the office, wherein there is no need to add communication devices to the peripheral devices existing in the office for communicating with the personal local area network of the invention, but in this case it will be sufficient that one transmitting device comprising these communicating means is arranged in the local area network of the office. This transmitting device can also be the same device as the user""s portable data processor.